Method of carton sealing

ABSTRACT

A MACHINE IS PROVIDED WHICH SEALS THE BOTTOM FLAPS OF EMPTY CARDBOARD CARTONS. IT COMPRISES MEANS TO RECEIVE PARTIALLY SET UP CARTONS, MEANS TO FIRST APPLY MELTED THERMOPLASTIC POLYMERIC RESINOUS ADHESIVE (KNOWN NORMALLY AS &#34;HOT MELT&#34; ADHESIVE) TO CLOSE FORWARD AND REAR LOWER FLAPS, MEANS TO THEN APPLY WATER SOLUBLE ADHESIVE TO OTHER AREAS OF THE SAME FLAPS, MEANS TO THEN CLOSE THE SIDE LOWER FLAPS AGAINST THE FLAPS TO WHICH ADHESIVE HAS BEEN APPLIED, MEANS TO SQUARE THE CARTON PRIOR TO APPLY PRESSURE, AND MEANS TO APPLY PRESSURE FROM ABOVE THROUGH THE INTERIOR OF THE CARTON AGAINST THE BOTTOM OF THE CARTON COMPRISING SAID FLAPS WHILE AT THE SAME TIME SUPPORTING SAID FLAPS FROM THE BOTTOM TO RESIST THE PRESSURE APPLIED FROM ABOVE.

NOV. 16, 19-71 P, N ETAL METHOD OF CARTON SEALING Original Filed May 24,1967 INVENTORFS A REIEHERT FRADENBURGH MORRIS E NE gONALD G. BY OHN NOV.16, 1971 p NEAL EI'AL METHOD OF CARTON SEAL-'1 N6 4 Sheets-Sheet 2Original Filed May 24, 1967 I mm w wE INVENTORS MORRIS I? NEAL DONALD G;REICHERT BY JOHN FRADENBURGH G N I A E US W L EC W 5 m E M Nov. 16, 19714 Shoe Ls-Sh0et 3 Original Filed May 24. 1967 lmh ow m a I 5 2. mm H.

INVENTOR.S

3 mm 0. REICHERT BY ATTORNEY Nov. 16,1971 RN -L ETAL 3,620,138

METIIOD'OFICARTON SEALING Original iled May 24, 1967 H 4UllOuLn-Jfihnol; 4

23o \gg 230 FIG. 7

FIG. 9

INVENTOILQ J MORRIS R N EAL' DONALD G. REICHERT BY JOHN FRADENBURGHUnited States Patent Oflice 3,620,138 Patented Nov. 16, 1971 3,620,138METHOD OF CARTON SEALING Morris P. Neal, deceased, late of Clearwater,Fla., by James L. Neal, executor, Clearwater, Donald G. Reichert, TarponSprings, and John Fradenburgh, Tampa, Fla., assignors to A-B-C PackagingMachine Corporation, Largo, Fla.

Original application May 24, 1967, Ser. No. 641,033, now Patent No.3,482,489, dated Dec. 9, 1969. Divided and this application Nov. 3,1969, Ser. No. 873,495

Int. Cl. B31b 1/26, 1/62, 49/02 US. Cl. 93--36.3 3 Claims ABSTRACT OFTHE DISCLOSURE A machine is provided which seals the bottom flaps ofempty cardboard cartons. It comprises means to receive partially set upcartons, means to first apply melted thermoplastic polymeric resinousadhesive (known normally as hot melt adhesive) to close forward and rearlower flaps, means to then apply water soluble adhesive to other areasof the same flaps, means to then close the side lower flaps against theflaps to which adhesive has been applied, means to square the cartonprior to applying pressure, and means to apply pressure from abovethrough the interior of the carton against the bottom of the cartoncomprising said flaps while at the same time supporting said flaps fromthe bottom to resist the pressure applied from above.

CROSS-REFERENCE This application is a division of Ser. No. 641,033 filedMay 24, 1967, now Pat. No. 3,482,489 issued Dec. 9, 1969, having thesame entitlement.

BACKGROUND AND SUMMARY This invention relates to a device for receivingpartially set up empty cartons with the lower front and rear flapsclosed, applying glue to these flaps and sealing the side lower flaps tothese flaps while the carton is empty to provide a carton with squarecorners without maintaining pressure on the sealed flaps for a longperiod of time. The cartons are generally of corrugated paper board orthe like.

The device may be considered an improvement on the sealing machinedisclosed in US. Pat. 2,572,047 issued on an application filed by one ofthe inventors of the device described herein.

As described in that patent and as well known in the art, it has beenknown to provide sealing machines which include certain elements. Theseinclude means to accept a carton which is lifted from a pile by a humanoperator, then partially set up by the operator and then introduced tothe machine by the operator in such fashion that two of the bottom flapsare closed, namely the front and rear bottom flaps, referring to thedirection in which the carton travels through the machine. Such elementsalso include means to apply glue to the two bottom flaps which have beenclosed and to then close the side flaps against these flaps. Althoughnot shown in the aforesaid patent, it is well known to then fill thecarton with packages and to then close the top flap, whereupon pressureis applied to the bottom flaps in order to hold them closed until theglue has set by causing the carton to travel between an upper and alower belt so that the bottom of the carton rests on the lower belt andpressure is applied to the top of the carton through the top flaps whichare closed and thence through the contents of the package to the bottomflaps.

Such machine have depended entirely upon the provision of contents, thatis, a plurality of packages such as cans, bottles or other smallcontainers, either filled or empty, in the carton so that pressure canbe applied to the top of the bottom flaps by applying pressure to thetop of the carton which pressure is transferred therefrom to the bottomflaps by the contents of the carton.

Such machines obviously are inoperative with cartons which do notcontain any contents, that is, empty cartons, because pressure appliedin such a machine to the top of the carton is not transferred to thearea of the bottom flaps in the manner necessary to hold the bottomflaps together. In such machines, pressure may be transmitted downwardby the walls of the carton to the outer edges of the bottom flaps butsuch pressure is ineffective to hold the inner (upper) surfaces of the(inner or first closed) flaps downward so that the bottom surfaces ofthe inner flaps adequately contact the upper surfaces of the outer orside flaps in order to cause all of the flaps to be held firmly togetheruntil the glue sets.

It is necessary that the sealing of the flaps is accomplished primarilywith water soluble glue of the type which requires that the surfaces atthe glue joints be held firmly together for on the order of one minuteor more for reasons of economy. Methods of fastening the bottom flapstogether which call for the use of other materials in place of watersoluble glue such as hot melt adhesives, rivets, staples or the like,are unsuitable because of the appreciably greater cost per cartonintroduced by the use of such substitutes.

OBJECTS It is therefore an object of the invention to provide a devicewhich provides for sealing together the bottom flaps of empty cartonswith water soluble glue.

Other objects will become apparent from the drawings and from thefollowing detailed description in which it is intended to illustrate theapplicability of the invention without thereby limiting its scope toless than that of all equivalents which will be apparent to one skilledin the art.

DRAWINGS In the drawings, like reference numerals refer to like partsand:

FIG. 1 is an elevation from one side with the head end of the machine atthe left and the rear end of the machine at the right;

FIG. 2 is a cross-sectional plan view taken on lines 22 in FIG. 1;

FIG. 3 is a cross-sectional elevation taken on lines 3-3 in FIG. 1;

FIG. 4 is a perspective view from the bottom of a carton after both hotmelt adhesive and water soluble glue have been applied;

FIG. 5 is a schematic, partially cross-sectional, partially cutaway viewof the portion of the apparatus for applying hot melt adhesive whichprovides a reservoir for the adhesive;

FIG. 6 is a schematic, partially cross-sectional, partially cutaway viewof the portion of the apparatus for applying hot melt adhesive whichincludes the nozzles from which the adhesive is dispensed onto thesurface to be adhered; FIG. 6 is on a much larger scale than FIG. 5;

FIG. 7 is a fragmentary cross-sectional view taken on lines 7--7 in FIG.3;

FIG. 8 is a fragmentary cross-sectional view taken on lines 8-8 in FIG.2; and

FIG. 9 is an enlarged elevation which constitutes an enlargement of aportion of FIG. 1.

DESCRIPTION Carton entrance portion Referring now to FIGS. 1, 2 and 3,at the head end of the machine indicated generally as 10 there isprovided 3 a carton receiving member 11 which may correspond to thecombination of members 14 and shown in US. Pat. No. 2,572,047. Cartons(which are also referred to as 7 cases throughout) which are partiallyset up by an operator are placed onto this member by an operator asshown in that patent. Side guide members 12 and 13 may be provided toalign the carton with the machine so that as the carton is forced intothe machine by the operator until it is grasped by belts 14 and 15(which correspond to belt 16 shown in the aforementioned patent), ittravels with its front and rear sides 24 and 25 disposed laterally withrespect to the machine and with its left and right sides 23substantially parallel with the direction of travel. As the case isplaced in the machine, its front and rear lower flaps 20 and 21,respectively, are closed by contact with member 11 as shown in FIG. 3.

Car-ton jam preventer Disposed below the path taken by flaps 20 and 21through the machine, there is provided a shaft extending laterally whichmay be rotated on its axis by the action of air cylinder 31 operatingthrough its piston 32 on crank 33 rigidly attached to shaft 30.Extending toward the head end of the machine from shaft 30 and rigidlyattached thereto are arms 34 which have pad or stop members 35 disposedat their ends and extending laterally. When air cylinder 31 is operated,members 35 are interposed in the path of the case through the machine.Parts 33, 34 and 35 are shown in dotted lines in this position and whenso interposed the case, even though grasped by belts 14 and 15, isprevented from traveling through the machine; the belts merely slidealong the left and right sides 23 of the carton. Near the head end ofthe machine there is provided switch having switch actuating member 41extending therefrom into the path of a carton through the machine, Whena case is carried into contact with member 41, it is forced into theposition shown in dotted lines at 41' in FIG. 2, whereupon switch 40 isactuated. A similar switch 42 is provided to ascertain the presence ofthe case further along in the machine by reason of switch actuatingmember 43 being moved by the case to actuate switch 42. Normally as thecase passes through the machine, switch 40 is first actuated andsubsequently switch 42 is actuated. However, if a case jams in a machineor more cases are present in the machine at one time than the machine isdesigned to accommodate, a case will be present opposite each of theswitches 40 and 42 and both switches will be opera-ted at the same time.When both switches are operated at the same time, means (not shown forsimplicity) are provided to actuate cylinder 31 to cause members 35 tobe interposed in the path of a case to prevent further cases from beingintroduced into the machine until the situation no longer obtains. Thusgenerally a case introduced in the machine is prevented in this mannerfrom being carried by the machine into contact with the next previouscase introduced into the machine.

Upper flap mechanism Also near the head end of the machine there isprovided switch 44 having actuator 45 to actuate switch 44 in responseto the presence of a case opposite the switch. Extending transverselybetween frame members 46 and 47, located above the path occupied by acarton in traveling through the machine, there is provided shaft 48rotatable on its axis. Attached to one or both frame members 46 and 47there is provided air cylinder 49 disposed so that when operated itspiston 50 acts on crank 51 which is rigidly attached to shaft 48, torotate shaft 48. Also rigidly attached to shaft 48 there is providedtucking member 52. Means are provided (not shown for simplicity) toactuate cylinder 49 in response to actuation of switch 44 so that crank51 and tucking member 52 are forced into the position shown in dottedlines at 51, and 52 to tuck the upper front flap 26 forward as shown inFIG. 3 as a case passes this portion of the machine. Thereafter it isheld in the forwardly extending position by contact with guide members53 against which it slides and when rear upper flap 27 is contacted byguide members 53 it is forced into the rearwardly extending position andheld in this position as it passes through the machine.

Attached to the same frame there are provided guides 54 which serve toprevent upper left and right flaps 28 from being folded inwardly so thatthey are prevented from interfering with the action of tucker 52 orguide 53 in controlling the positions of the front and rear upper flaps26 and 27. When the front upper flap contacts guide rails 54, it may befolded backward slightly. But guide rails 54 tend to pass in the slotbetween the front and rear flaps and the side flaps. In any event, guide54 prevents the slide flaps from creating such interference until thepositions of the front and rear flaps have been adequately controlled bymembers 52 and 53.

Provision for cases of different sizes To provide for readyadjustability of the machine to accommodate cases which vary widely inheight, width and length, within the design capability of any specificembodiment, several features are provided. Thus guide members 53, upperfront flap tucking mechanism comprising elements 49, 50, 51 and 52 andguide members 54 are carried on the frame which comprises members 46 and47 is supported from transverse shafts 55 and 56.

Attached at each end of shafts 55 and 56 there are provided pinions 57which are engaged with racks 58 provided as portions of uprights 59, 60,61 and 62. Also attached to each of shafts 55 and 56 is a larger pinionrespectively 63 and 64 engaged respectively with worm gears 65 and 66attached to longitudinally extending shaft 67. By operating crank 68attached to shaft 67, the entire frame work comprising members 46 and 47and controlling the height of guides 53, 54 and tucker 52 may be readilyvaried upwardly or downwardly to accommodate cases of greater or lesserheight.

To accommodate varying widths of cartons, belts 14 and 15 are mountedand driven in the same manner as shown in Pat. No. 2,572,047. Thus crankcorresponds to crank 50 and is attached to shaft 151 which correspondsto shaft 51. Chain 153 corresponds to chain 53 to cause shaft 155 whichcorresponds to shaft 55 to be rotated the same amount as shaft 151.Shaft 163 corresponds to shaft 63 and carries pulleys around which thehead ends of belts 14 and 15 are carried. Shafts 159 correspond toshafts 59 and carry pulleys around which the rear ends of belts 14 and15 are trained. Shaft 171 corresponds to shaft 71 and is driven by motor164 through chain 168 which corresponds to chain 68a. Bevel gears 173correspond to bevel gears 73 and are slidable on splined shaft 171.Bevel gears 174 correspond to bevel gears 74 and are driven by bevelgears 173 to drive shafts 159 to which gears 173 are attached, tothereby drive the belts. The lateral spacing of the belts may be readilyvaried by simply operating crank 150 as described in the aforesaidpatent.

Glue applicator Glue applicator 70 corresponds to that shown in theaforesaid patent or may be a modification and comprises receptacle 71which is received on transverse bars 72 but differs from the applicatordescribed in said patent in that the rollers 73 which contacts the lowerflaps comprises a plurality of discs 74 mounted on a common shaft 75. Asdescribed in the aforesaid patent, the applicator is driven by gearswhich engage with the gears carried by shaft (which corresponds to shaft70) which is driven through chain 168' (corresponding to chain 68) frommotor 164. As the carton travels over applicator 70, it is carried onrails 76 and 77 which constitute extensions of member 11. Contactbetween discs 74 and bottom flaps 20 and 21 causes glue to be disposedon these flaps in strips as indicated at 79 in FIG. 4.

Water soluble adhesive or glue 74 is supplied to receptacle 71 fromreservoir 78 in the manner discussed in the above patent in conjunctionwith reservoir 38.

Means to apply hot melt adhesive Disposed between applicator 70 and therear end of the machine there is provided dispensing head 80 to dispensemelted thermoplastic polymeric resinous adhesive known as hot meltadhesive through nozzles 81 as strips 83 on the lower flaps 20 and 21(FIG. 4). Strips 83 are deposited on portions which are unoccupied bystrips 79. Although four nozzles are shown so that two strips areapplied on each side of the center, there may be provided only twonozzles so that only one strip is provided on each side of the center orthere may be provided three or more nozzles on each side. Means forapplying such hot melt adhesive is shown in more detail in FIG. 5.Adhesive which may be powdered, flake, granulated or pellet form isintroduced into container 85 which is covered by lid 86. It is heated tomolten state by means which for simplicity are not shown and maintainedby suitable controlling means (which also for simplicity are not shown)at a temperature such as for example 325 F. The melted adhesive 87 mayflow downward through check valve 88 into cylinder 89 in which piston 90is adapted to move slidably, being driven by the piston 91 of aircylinder 92. When cylinder 92 is actuated, piston 90 is operated todrive a quantity of adhesive through a heated tube as indicated at arrow93 to inlet 94 of the dispensing head 80. From inlet 94 the hot meltadhesive flows through passage 95 into each of valves 96. In each valve96 there may be provided a stem having a sliding piston portion 97 towhich there may be attached spring guide portion 98. Spring 99 maysurround portion 98 and may act against the interior of the body of thedispensing head to bias portion 97 upwardly. Extending upwardly frompiston portion 97 there may be provided sealing member 100 which sealsat 101 against the interior of tip portion 81 which is threadedlyreceived at 102 in the body of the dispensing head. Seals 103 areprovided as shown.

In use, when the pressure of the hot melt adhesive in the dispensinghead is increased by operation of piston 90, the pressure is transmittedthrough passage 95 to the upper side of piston member 97 thereby forcingthe valve stem with its severalparts downward against the action ofspring 99 and unseating sealing member 100 from tip 81 at 101 to allowadhesive to flow out of the orifice 104 in tip 81. The force exertedupwardly on member 100- and therefore the pressure of the seal at 101may be adjusted by screwing tip 81 into or out of the body to someextent. The dispensing head is heated and maintained at a suitabletemperature by means which for simplicity are not shown. Such atemperature may be for some adhesives exemplified by a temperature of350 F. or 375 F. Depending on suitable adjustment of the valves in thedevice, adhesive may be projected as much as 20 feet from the nozzletips if desired. Generally speaking, the nozzles are located between and/2 inch below the surface upon which adhesive is to be projected.

Switches 110, 112, 114 and 116 provided respectively with actuating arms111, 113, 115 and 117 control actuation of cylinder 92 and thereby ofpiston 90 to control the length and longitudinal position of the startand end of each strip of adhesive. As a case contacts actuator 111 andswitch 110 is thereby actuated, movement of piston 90 begins anddeposition of strips 83 of adhesive as shown in FIG. 4 is begun. Whenthe case contacts actuator 113 and actuates switch 112, actuation ofcylinder 92 ceases and deposition of adhesive ceases. Then when a casecontacts actuator 115 of switch 114, cylinder 92 is again actuated anddeposition of adhesive is again initiated and when the case contactsactuator 117 to operate switch 116, deposition of adhesive is againcaused to cease.

Suitable thermoplastic polymeric resinous materials which may usefullyserve as hot melt adhesives include, as examples, modified low molecularweight polyolefin resins and blends thereof with materials such as otherresins, for example, chlorinated bip'henyl, polyterpene, x-methylstyrene or the like or with microcrystalline wax. The particularadhesive to be used may depend upon the surface characteristics of thefaying surfaces which are to be joined by the adhesives, the ambienttemperature,

the desired setting time and so forth.

Lower flap tacking station Before a carton enters this station, itslower side flaps are closed against the inner flaps. At the station,pressure is applied to opposite sides of the lower flaps for asufficient time, usually appreciably less than one second, for the hotmelt adhesive to set enough to tack the lower flaps together. Then thecarton is carried out of the machine and the hot melt adhesive, whichhas now set, holds the lower flaps tacked together until the watersoluble adhesive has had time to set and to provide most of the strengthof the joints.

After the case leaves rails 76 and 77 which terminate near the hot meltadhesive dispensing head, it is supported from below on the upper edgeof vertical plate 1120 and its two lower side flaps 22 are closed byclosing members '121 which correspond to members 76 shown in theaforementioned patent. Near the rear end of the machine, extendingtransversely with respect thereto, there is provided square shaft 122,journalled at 123 and 124 to rotate on its axis and biased to rotate ina counter-clockwise direction as viewed in FIG. 3 or clockwise in FIG.8, by the action of chain 125 which has weight 127 attached to its endand extends over sprocket 126 which is attached to the shaft. Furtherrotary movement in this direction is prevented by the action of pin 128against cam 129 as shown in FIGS. 1 and 9. Members 130 are receivedslidingly on shaft 122 and may be fixed in place on the shaft by theaction of screws 132 and each comprises a tab 131 which may extend upinto the path of a carton travelling through the machine. When a cartoncontacts tabs 131, the shaft is forced to rotate to the position inwhich tabs 131 have the position shown in dotted lines at I131 whereinthe tabs extend vertically upward and if the case is at all skewed atthe time it first contacts one or the other of these members, it isforced to become square by the action of both the belts in bringing eachside forward until each lower front corner contacts one of said tabs.When the case has become squared so that the front side 24 or its lowercorners contact both of members 131, then each of belts 14 and 15 slideby the case while the case is retained stationary. When the shaft 122 isrotated into the position indicated by tab 131', cam member 134 contactsswitch actuator 135 as shown in FIG. 1 and switch 136 is operated.

Two lower pressure plates 138 are disposed respectively on each side ofplate 120 below the position the case occupies when in contact withmembers 131. Each of plates 138 is supported respectively by a verticalsliding member '140 which slides in ways 1441. Plates 138 are caused tooccupy the position shown in dotted lines 138' and thereby bear againstthe lower surface of flaps 20 and 21 when cylinder 142 is actuated toactuate, through its piston 143-, crank arm 144 pivoted at 145 andprovided at 146 with a member slidably received in plate to convert thecircular motion at 146 of crank 144 into vertical reciprocatory motionof member 140. Above plates 138 there is provided a pressure-applyingshoe 200. Shoe 200 is supported from the lower end of piston rod 201extending from cylinder 202 in which rod 201 operates. Guide member 203is provided extending upwardly through boss 204 which in turn issupported from plate 205 which extends from plate 206 to which cylinder202 is attached. The rear of plate 206 is serrated or has the form of amodified type of rack as shown at 207 and also as 7 shown at 207, itengages a corresponding surface extending from plate 208. Plates 206 and208 are held together by bolts 209. By loosening bolts 209, the verticalposition of plate 206 with respect to that of 208 may be easily adjustedand a new and different vertical relationship between the two may bereadily established by retightening the bolts whereupon thecorresponding toothed or ribbed surfaces engage as shown at 207 andsecurely maintain the vertical relationship undisturbed. This means ofadjusting makes it possible to adjust the height of shoe 200 to clearthe uppermost part of a carton at the center, that is, to clear flaps 26and 27 as the carton travels under the shoe when the shoe is in theraised position. Plate 208 is attached to brackets 210 and 211, only oneof which is shown in FIG. 3, the other being on the other side of themachine. Brackets 210 and 211 are supported from shaft 212 to hingeablyrotate around the axis thereof, shaft 212 being supported from framemembers 213 and 214. Bar 215 is provided extending between the rear endsof frame members 213 and 214 and pivotally attached at 216 to a lugextending from said bar is air cylinder 217 having piston 218 which atits lower end is pivotally attached to the lower end of plate 208 asshown at 219.

When the movement of a case has been interrupted near the rear of themachine by the action of tabs 131 so that it is held stationary in themachine and the belts slide along the side of the case, shoe 200 isdisposed to be introduced through the interior of the case into contactwith the upper surfaces of lower front and rear flaps 20 and 21 to pressthese flaps down against flaps 22 to thereby hold the faying surfaces towhich adhesive has been applied together by forcing the inner flapsagainst the outer flaps which are supported by plates 138.

For this purpose, shoe 200 is carried downward into the positionindicated at 200 by piston 201 when cylinder 202 is actuated. Theoperation of guide member 203 and boss 204 serves to prevent the shoefrom rotating in an undesirable manner in a horizontal plane around avertical axis. As shoe 200 begins its upward travel, cy inder 217 may beactuated to withdraw piston 218 into the cylinder 217 so that the heelof shoe 200 indicated at 200 describes the path indicated by dottedlines 220' in returning to the position shown in full lines and thus ata point intermediate between that occupied at 200' and that occupied asshown in full lines, shoe 200 may occupy a position shown approximatelyby dotted lines 220". This motion is desirable in order to make itpossible for the movement of a case forward in the machine to be allowedto be initiated before shoe 200 has been entirely removed fromtherewithin.

Timing of this portion of the device is as follows: As a result ofrotation of shaft 122 until tabs 131 extend in a vertical position, cammember 134' is rotated until its surface 134 occupies the position shownin dotted lines at 134" and forces member 135 into the position shown indotted lines at 135'.'Member 135 is both a cam follower and the actuatorfor switch 136 (which is a combined limit switch and timer) and when itis moved to the position shown at 135', switch 136 is actuated.Actuation of switch 136 is set to operate cylinders 142 and 202.Normally pressure plates 138 reach the position shown at 138' before orat the same time shoe 200 reaches the position shown at 200. After shoe200 and plate 138 have been at the positions shown at 200 and 138 for asuitable time, the action of timer switch 136 causes actuation ofcylinders 142 and 202 to cease whereupon members 200 and 138 arereturned by springs (contained in the cylinders) to their positionsshown in full lines. Timer switch 136 is set to provide a dwell ofmembers 200 and 138 at 200 and 138 for any suitable time such as from to3 seconds. When actuation of cylinders 142 and 202 ceases and shoe 200starts to travel upwardly, cylinder 217 is actuated. The combined upwardand forward motion of shoe 200 is thus initiated. At the same timecylinder 217 is actuated, solenoid 228 (FIGS. 1 and 6) is actuated towithdraw pin 128, which is connected to its core, from surface 129.Surface 128 is a portion of cam 129 which is attached to shaft 122.Thus, when pin 128 is withdrawn from the impingement on cam member 129,belts 14 and 15 then cease to slide by sides 22; they grip the sides andimmediately start carrying the case out of the machine and square shaft122 may rotate to allow tabs 131 to be forced by the case which bearsagainst them being carried forward and over the tabs until they occu ythe position shown in dotted lines at 132" so that a case may passfreely thereover and out of the machine. At the same time, of course,cam 134 which is securely fixed to shaft 122, rotates until surface 134occupies the position shown at 134'.

As soon as a case has passed out of the machine, the weight 127 acts tocause shaft 122 to be returned to the position indicated by tabs 131 andsurface 134 in full lines, being prevented from further rotation by theaction of stop member 225, which is connected to shaft 122, contactingstud 226.

Generally speaking, a water soluble glue or adhesive, usually of aproteinaceous or carbohydrate type, is usually utilized for sealing theflaps of cartons and especially cases comprising corrugated board andsuch glue generally requires from 15 seconds to seconds to set, that is,reach a degree of tack sufiicient that pressure on the joint may bereleased and the remainder of setting may be accomplished withoutcontinuing to maintain pressure on the joint. To maintain such pressureon the joints between the bottom closed flaps in an empty carton wouldentail either very complex, expensive and space-consuming machinery orwould require a very low rate of production if each box were to bemaintained at a station for the time required to accomplish suchsetting. The time of setting is normally dependent on such factors asambient temperature and humidity, moisture in the surfaces, porosity ofthe surfaces, physical and chemical nature of the surfaces, viscosity ofadhesive, concentration of solids in the adhesive, type of adhesive, andthe like. The manner of adjustment of such factors or adjustment to suchfactors is well known in the industry and need not be elaborated here.

Hot melt adhesives on the other hand are relatively expensive andgenerally so expensive as to be prohibitive in being used for someclosure purpose where water soluble glue may suitably be used.Nonetheless, such an adhesive may be provided to set in from second to 3seconds depending upon such factors as the type of adhesive used, thetemperature of application. chemical and physical nature of the surfacesto be adhered, ambient temperature and humidity and the like. Pressuremust be maintained on a joint containing such an adhesive for a timesufiicient to allow tack to be developed so that setting can becompleted without continuing to maintain the pressure on the joint. Thistime may depend on the size of the package, the characteristics of thematerial of which the carton is made which determine the tendency offlaps to spring open, the amount of adhesive applied, the board surfacefinish, characteristics of the adhesive, room temperature, boardtemperature, adhesive temperature, and so forth. However, generallyspeaking, it is possible to adjust or balance these factors so thatpressure need not be maintained on the joints for more than about .3 to.8 seconds in order to provide sufiicient tack so that the joint may bemaintained under pressure. By providing the device as describedhereinabove, the desirable features of hot melt adhesives for thepresent application, namely their rapid setting rate, and the desirablefeatures of water soluble adhesives, normally their low cost, arecombined to provide a joint wherein most of the strength is provided bythe relatively large volume of the relatively low cost water solubleglue whereas relatively extremely high rates of operation are providedby utilizing the rapid setting characteristics of small quantities ofhot melt a(l hesive. Accordingly, the rate at which plates 138 and shoe200 are cycled may be relatively great especially if operating undercircumstances where pressure need be applied for only .2 or .3 of asecond.

Since a high rate of operation is desirable, the pressure is normallyapplied for the minimum of time necessary to provide a suflicient degreeof tack of the hot melt adhesive at the joints so that the hot meltadhesive will tack the lower flaps together sufliciently to hold themtogether after the carton has left the machine for a time sufficient toallow the water soluble glue to set and develop its strength whereuponthe dried water soluble glue provides most of the strength of the joint.

As shown in FIG. 6, idlers 230 may be provided adjacent the inner lowersurfaces of belts 14 and 15 respectively to push portions of the beltsaway from spaces which may be occupied by tabs 131 so that the tabs maybe caused to bear against the lower outer corners of the case directlyrather than merely against portions of the lower edge of the front side24, in between the corners. Since the case is carried into contact withtabs 131 with a good deal of force by belts 14 and 15, it has been founddesirable to cause the tabs 131 to contact the corners rather than aportion of the lower edge of side 24 between the corners. If tabs 131are located inwardly from the corners so that they are not contacted bythe corners but merely by portions of the lower front edge of side 24,they tend to become imbedded in the carton to a certain extent and sincethe extent of the imbedment is usually different for one than for theother, the case is not caused to be properly squared, this imbedmentbeing a result of the fact that the belts bring the case into contactwith the tabs with a considerable amount of force.

It may thus be seen that the invention is broad in scope and includessuch modifications as will be apparent to those skilled in the art andis to be limited only by the claims.

Having thus described our invention, we claim:

1. The method of sealing side flaps of an empty carton to end flaps ofan empty carton which comprises the combination of the steps of:

moving said carton along a path while maintaining said end flaps inclosed position and said side flaps in an open position,

providing a plurality of small reservoirs of thermoplastic polymericresinous adhesive which sets from liquid to solid in from second to 3seconds, maintaining said adhesive in said reservoir at an elevatedtemperature to maintain it in a liquid form, projecting intermittentstreams of said liquid adhesive 10 from said reservoirs against at leastone pair of said flaps from means disposed out of contact with saidflaps, as the carton moves along said path, regulating the intermittencyof said streams to provide strips of said adhesive on said flaps whereinsaid strips are characterized by terminating at points spaced inwardlyon the flaps from the edges of the flaps, providing at least onereservoir of liquid water soluble adhesive which sets in over 15seconds, providing roller discs which dip into said liquid water solubleadhesive and are positioned to contact said pair of flaps, moving saidcarton along said path so that said pair of flaps contact said rollerdiscs and strips of said liquid water soluble adhesive are provided onsaid flaps, then closing the side flaps into contact with the end flapsand applying pressure to the inner surfaces of the end flaps andsimultaneously applying pressure to the outer surfaces of the sideflaps, maintaining said pressure on said side and end flaps for at least0.1 second until said thermoplastic polymeric resinous adhesive issufiiciently set to hold the flaps together until said water solubleadhesive sets. 2. The method of claim 1 wherein said adhesives areapplied to said end flaps.

3. The method of claim 1 wherein said strips of Water soluble adhesiveare interposed between said strips of thermoplastic polymeric resinousadhesive.

References Cited UNITED STATES PATENTS 2,572,047 10/ 1951 Neal 118-2582,977,861 4/1961 Gibb 93-51 3,253,389 5/1966 Miller 53-374 3,354,606-11/1967 Miller 53-76 1,953,183 4/1934 McLaurin 93-56 PD 2,353,311 7/1944Karlson 93-35 3,342,116 9/1967 Roesner 93-36 MM 3,374,604 3/1968 Roesner53-75 WAYNE A. MORSE, JR., Primary Examiner US. Cl. X.R.

53-383; 93-36 MM, 49 M, 56 PD

